1. Field of the Invention
The present invention relates to a system and method for compensating for anode gain non-uniformity in a multi-anode position sensitive photomultiplier tube, and more particularly, to a system and method for compensating for anode gain non-uniformity in a multi-anode position sensitive photomultiplier tube, in which a compensation unit is disposed between the multi-anode position sensitive photomultiplier tube and a position detection circuit unit and configured to uniform a current signal inputted to the position detection circuit unit, thereby compensating for anode gain non-uniformity.
2. Background of the Related Art
A nuclear medicine imaging apparatus is widely used for a variety of diagnosis and medical treatments, such as an examination of energy metabolism and a neuron receptor system by imaging the distribution of radiopharmaceuticals within the body. Representative nuclear medicine equipments, such as a gamma camera, a Single Photon Emission Computed Tomography (SPECT) apparatus, and a Positron Emission Tomography (PET) apparatus, are based on a scheme for converting photons, generated through the interaction of gamma rays and scintillation crystals, into electrical signals and then imaging a gamma-ray interaction position using electronic circuits and a computer program. Here, a device for converting weak light, generated within the scintillation crystals, into electrons, amplifying the electrons, and outputting the amplified electrons as a signal is a photomultiplier tube.
The photomultiplier tube can have various forms from a cylinder form to a quadrangle form. From among them, a Multi-anode Position Sensitive Photomultiplier Tube (PS-PMT) has a wide effective area because it has several tens to several hundreds of anodes arranged with the high integration. Thus, the PS-PMT is advantageous for image devices using scintillation crystals of a small cross section. In the PS-PMT, however, the anodes have different gains for a uniformly incident light source, respectively. Consequently, a distortion can occur in determining a gamma-ray interaction position because of such gain non-uniformity.
Accordingly, in order to increase accuracy in detecting gamma rays interaction positions, there is a need for compensating for anode-based (or channel-based) gain non-uniformity in the PS-PMT.